This invention relates to a catheter apparatus, system, and method for intravascular two-dimensional ultrasonographic imaging, and more particularly to such an apparatus, system, and method for guiding and monitoring interventional therapy to reduce vascular stenosis.
Ultrasonic two-dimensional imaging apparatus and systems have heretofore been provided for use in endoscopy for examining the gastrointestinal tract. Such a device is disclosed in U.S. Pat. No. 4,494,549. Such devices, however, have been relatively large and inflexible and are completely unsuitable for use within the vascular system of the human body. In addition, there is no provision for guiding such devices into specific branches of blood vessels.
There is, therefore, a need for a new and improved catheter apparatus, systems, and methods which can be utilized for performing intravascular two-dimensional ultrasonographic imaging. It would be particularly desirable if such imaging apparatus and methods could be combined with a variety of intravascular therapeutic modalities, such as angioplasty atherectomy, laser ablation, and the like, in order to provide simultaneous imaging and recanalization procedures.
According to the present invention, a method for imaging the interior of a blood vessel comprises scanning an ultrasonic signal in a preselected pattern about said interior. By receiving ultrasonic energy reflected from the interior surface of the vessel, including any stenosis or occlusion present, an image or profile of the blood vessel may be produced. Conveniently, the ultrasonic signal is generated by a transducer located at the distal end of a vascular catheter comprising a flexible tubular member. The transducer may be manipulated directly to sweep the ultrasonic signal in a desired pattern, including radial, planar, and conical. Alternatively, the transducer may be fixed within the catheter and a reflective surface manipulated to sweep the ultrasonic signal in a desired pattern. The imaging method of the present invention is advantageously combined with interventional therapeutic techniques to reduce vascular stenosis, where the stenosis may be imagined prior to, during, and after intervention to help direct the interventional activity to where it will be most effective.
In general, it is an object of the present invention to provide a catheter apparatus, system, and method for intravascular two-dimensional ultrasonography.
Another object of the invention is to provide an apparatus, system, and method of the above character which has a high resolution capability.
Another object of the invention is to provide an apparatus, system, and method of the above character which can be utilized for assessing endovascular lesions.
Another object of the invention is to provide an apparatus, system, and method of the above character which can be utilized for monitoring the results of interventional therapy.
Another object of the invention is to provide an apparatus, system, and method of the above character which can be used with angioplasty, atherectomy, laser ablation, drug deliver, and similar vascular interventional methods and devices.
Another object is to provide an apparatus, system, and method capable of selective cannulation of branch vessels.
Additional objects and features of the invention will appear from the following description in which the preferred embodiments are set forth in detail in conjunction with the accompanying drawings.